Articulated vehicles, such as articulated dump trucks (ADT's), are known in the art. For example, ADT's typically include a cab portion having a first frame supporting an operator cab, and a trailer portion having a second frame supporting a dump body. The dump body may be configured to contain a load and is typically coupled to an actuator for angular movement relative to the second frame. The first frame and the second frame may be operably coupled through an articulation joint. A front wheel assembly coupled to the first frame may provide rolling support to the cab portion, and a rear wheel assembly coupled to the second frame may provide rolling support to the trailer portion.
Articulated vehicles may approach an overspeed condition when the powertrain components reach speeds exceeding design limits. For example, an overspeed condition may occur when the articulated vehicle reaches a top speed in a top gear and the vehicle continues to gain speed. Such an overspeed condition may present a risk of damage to the engine, transmission, or other drivetrain components.
According to an embodiment of the present disclosure, a work vehicle is provided including an engine having a throttle device and a transmission coupled to the engine. A chassis includes a cab portion, a trailer portion, and a coupling device positioned between the cab portion and the trailer portion. The cab portion includes a first frame and the trailer portion including a second frame, and the coupling device is configured to provide pivoting movement of the trailer portion relative to the cab portion. A front wheel assembly is configured to support the cab portion. The front wheel assembly includes a first axle and a pair of wheels coupled to the first axle. A rear wheel assembly is configured to support the trailer portion. The rear wheel assembly includes a second axle and a pair of wheels coupled to the second axle. A drive shaft is coupled between the first wheel assembly and the second wheel assembly. A brake is coupled to at least one of the front and rear wheel assemblies and is configured to apply a braking force to the at least one of the front and rear wheel assemblies. A sensor is configured to detect a speed of the vehicle, and a controller is in communication with the brake and the sensor. The controller is configured to control an opening of the throttle device of the engine. The controller is configured to automatically reduce the opening of the throttle device upon the detected vehicle speed being outside a first threshold range and to automatically actuate the brake upon the detected vehicle speed being outside a second threshold range, the second threshold range being greater than the first threshold range.
According to another embodiment of the present disclosure, a vehicle is provided including a front portion having a front frame, an engine supported by the front frame, and a transmission coupled to the engine. The vehicle includes at least one of a retarder coupled to the transmission and a parasitic load coupled to the engine. Activation of the at least one of the retarder and the parasitic load is configured to inhibit a rotation of the transmission. A front wheel assembly is operably coupled to the front frame to support the front portion. The front wheel assembly includes a first axle and a pair of wheels coupled to the first axle. The vehicle further includes a trailer portion including a rear frame. A rear wheel assembly is operably coupled to the rear frame to support the trailer portion, the rear wheel assembly including a second axle and a pair of wheels coupled to the second axle. A frame coupling is positioned between the front frame and the rear frame, the frame coupling being configured to provide pivoting movement between the front frame and the rear frame. A drive shaft is coupled between the front wheel assembly and the rear wheel assembly. A brake is coupled to at least one of the front and rear wheel assemblies and is configured to apply a braking force to the at least one of the front and rear wheel assemblies. A sensor is configured to detect a speed of the transmission. A controller is in communication with the brake, the sensor, and the at least one of the retarder and the parasitic load. The controller is configured to automatically activate the at least one of the retarder and the parasitic load upon the detected transmission speed being outside a first threshold range and to automatically actuate the brake upon the detected transmission speed being outside a second threshold range, the second threshold range being greater than the first threshold range.
According to yet another embodiment of the present disclosure, an overspeed protection method for a vehicle is provided. The method includes providing a vehicle including a cab portion, a trailer portion, a drive train, and a coupling device positioned between the front portion and the trailer portion. The coupling device is configured to provide pivoting movement between the trailer portion and the cab portion. The cab portion includes a front wheel assembly, and the trailer portion includes a rear wheel assembly. At least one of the front wheel assembly and the rear wheel assembly include a brake. The drive train includes an engine and a transmission coupled to the engine. The method further includes detecting a speed of the drive train, comparing the detected speed to a first threshold range, and reducing a throttle demand to the engine upon the detected speed being outside the first threshold range. The method further includes comparing the detected speed to a second threshold range, the second threshold range being greater than the first threshold range, and activating the brake upon the detected speed being outside the second threshold range.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.